Products in unit dose form are found to be very attractive and convenient to some consumers because they avoid the need of the consumer to measure the product thereby giving rise to a more precise dosing and avoiding wasteful overdosing or underdosing. Lately, products in unit dose form have become one of the preferred forms for the user due to the easiness of use, in particular water-soluble pouches which present the added advantage of no need to unwrap.
Water-soluble packs consist of water-soluble enveloping material which encloses a cleaning composition. It is a common believe that compositions contained in the pack need to be free of water or have a very low level of free water otherwise the enveloping material would dissolve or the free water would negatively impact on the stability of the pack. Traditionally, water soluble packs contain compositions in solid form or in the form of anhydrous liquid (i.e. compositions with very low levels of free water).
Some cleaning ingredients are provided in the form of aqueous solutions. These ingredients can be difficult or costly to include in a solid cleaning composition or to include in an anhydrous liquid composition which would require to dry the water (involving a high use of energy) and to dissolve the active ingredient in an organic solvent. Examples of these cleaning ingredients include polymers, builders, surfactants, etc.
Current methods of incorporating liquid ingredients into solid detergent compositions include absorbing the liquid ingredient onto a solid carrier, for example by mixing, agglomeration or spray-on techniques. Typically, solid detergent compositions comprise only low amounts of these liquid detergent ingredients due to the difficulty and expense of incorporating these liquid ingredients into as solid detergent. Furthermore, the incorporation of liquid ingredients into solid detergent compositions can impact on the dissolution characteristics of the composition (for example as the result of forming surfactant gel phases), can increase the moisture pick-up by water sensitive ingredients and can also lead to problems of flowability. It would be advantageous to have a cleaning composition which allows the different ingredients to be in their natural state i.e., aqueous liquid or solid. This would facilitate the manufacturing process, increase the components stability and furthermore allow the delivery of liquid ingredients prior or post to the delivery of solid ingredients. For example differential dissolution of active ingredients would be beneficial in the case of enzyme/bleach compositions to avoid oxidation of enzymes by the bleach in the dishwashing liquor. It would also be advantageous to separate bleach from perfume.
In recent years there has been a tendency towards the elimination of phosphate from detergents. This elimination does not only have repercussions on the cleaning of the detergent but also on the stability. Phosphate can act as a moisture sink thereby protecting other moisture sensitive ingredients, such as enzymes, contained in the detergent. A present challenge is the stability of moisture sensitive ingredients in compositions free of phosphate.
A problem found with cleaning products in the form of multi-compartment packs, enveloped by water-soluble material, is that the pack can pick up moisture from the surrounding environment and moisture can also migrate between compartments, negatively impacting the stability of the cleaning composition.
In view of the above discussion, an objective of the present invention is to provide a more versatile cleaning product being able to accommodate aqueous compositions.